Re: [Qemu-devel] [PATCH for-2.4 0/2] AioContext: fix deadlock after aio_context_acquire() race

[Cornelia Huck <cornelia.huck@de.ibm.com>]

On Tue, 28 Jul 2015 09:07:00 +0200
Cornelia Huck <cornelia.huck@de.ibm.com> wrote:

> On Mon, 27 Jul 2015 17:33:37 +0100
> Stefan Hajnoczi <stefanha@redhat.com> wrote:
> 
> > See Patch 2 for details on the deadlock after two aio_context_acquire() calls
> > race.  This caused dataplane to hang on startup.
> > 
> > Patch 1 is a memory leak fix for AioContext that's needed by Patch 2.
> > 
> > Stefan Hajnoczi (2):
> >   AioContext: avoid leaking BHs on cleanup
> >   AioContext: force event loop iteration using BH
> > 
> >  async.c             | 29 +++++++++++++++++++++++++++--
> >  include/block/aio.h |  3 +++
> >  2 files changed, 30 insertions(+), 2 deletions(-)
> > 
> 
> Just gave this a try: The stripped-down guest that hangs during startup
> on master is working fine with these patches applied, and my full setup
> works as well.
> 
> So,
> 
> Tested-by: Cornelia Huck <cornelia.huck@de.ibm.com>

Uh-oh, spoke too soon. It starts, but when I try a virsh managedsave, I
get

qemu-system-s390x: /data/git/yyy/qemu/async.c:242: aio_ctx_finalize: Assertion `ctx->first_bh->deleted' failed.